D

Glossary of terms for managing wholes

desertification - The process by which formerly productive land turns into desert. Symptoms include increased incidence of flood and drought, declining biomass and soil organic matter, and increased bare ground. Though rainfall may remain constant, plant and animal communities shift to those more tolerant of low moisture, and biodiversity declines.

Desertification [is] itself only a symptom of a larger problem-the loss of biodiversity (the diversity of species, the genetic diversity within them, their age structure and, in general, the mass of life, or "biomass," present). Day by day, and acre by acre, as an environment loses biomass, diversity of species, genetic variation and age structure, it gradually loses vigor until, like the cancer victim, it dies. When, at death's door, we finally take notice, we refer to the skeletal remains as "desertification."

destructive grazing - Grazing that damages plants, and therefore land. Grassland plants coevolved with herding grazers, and are well adapted to severe grazing. It won't hurt them as long as they get an adequate recovery period before getting grazed again. Too-frequent grazing weakens and may kill them. See overgrazing for details.

destructive rest - Resting of land from disturbances such as grazing, trampling, and fire, sufficiently long to cause ecosystem damage. Destructive rest is almost entirely confined to brittle and semi-brittle environments,.

disturbance - Processes such as fire, grazing, soil compaction from vehicle tires or animal movement, trampling, bulldozing, and landslides, which physically disrupt and alter a landscape. Prolonged rest from disturbance allows some types of ecosystems to flourish, but damages others.